Simplified isophthalic acid process for modifying PET

Abstract

Disclosed are modified PET polymer compositions and process for making modified PET polymer compositions by reacting purified terephthalic acid and non-hydrogenated isophthalic acid with ethylene glycol. Compositions with acceptable visual appearance, such as clarity and color, can be made at typical modification levels for many packaging application. Disclosed are also shaped articles and the process for making shaped articles of the modified PET polymer composition.

1. A process for producing a modified PET polymer comprising: reacting non-hydrogenated isophthalic acid with terephthalic acid and ethylene glycol to produce the modified PET polymer comprising
 i. a carboxylic acid component comprising:
 a. about 0.5 mole % to about 7 mole % isophthalic acid residues; 
 b. at least about 90 mole % terephthalic acid residues; and 
 
 ii. a hydroxyl component comprising at least about 90 mole % ethylene glycol residues, 
 based upon 100 mole % carboxylic acid residues and 100 mole percent hydroxyl component residues in the modified PET, and having a disc L* of at least about 60 and a disc b* of less than about 5. 
 
     
     
       2. The process of  claim 1 , wherein the modified PET polymer comprises:
 i. the carboxylic acid component comprising
 a. about 0.5 mole % to about 7 mole % of the isophthalic acid residues; 
 b. at least about 93 mole % of the terephthalic acid residues; and 
 
 ii. the hydroxyl component comprising at least about 95 mole % of the ethylene glycol residues, 
 based on 100 mole percent of the carboxylic acid component residues and 100 mole percent of the hydroxyl component residues in the modified PET polymer. 
 
     
     
       3. The process of  claim 1 , wherein the carboxylic acid component comprises about 1 mole % to about 4 mole % of the isophthalic acid residues. 
     
     
       4. The process of  claim 1 , wherein the non-hydrogenated isophthalic acid comprises at least:
 i. about 100 ppm to about 10,000 ppm 3-CBA; 
 ii. about 20 ppm to about 500 ppm fluorenones; or 
 iii. at least about 50 ppm to about 10,000 ppm 3-CBA in combination with at least about 10 ppm to about 500 ppm fluorenones. 
 
     
     
       5. The process of  claim 4 , wherein the non-hydrogenated isophthalic acid comprises at least:
 i. about 500 ppm to about 2,000 ppm of the 3-CBA; 
 ii. about 50 ppm to about 200 ppm of the fluorenones; or 
 iii. at least about 100 ppm to about 2,000 ppm of the 3-CBA in combination with at least about 25 ppm to about 200 ppm of the fluorenones. 
 
     
     
       6. The process of  claim 1 , wherein the modified PET polymer has a disc L* of at least about 70. 
     
     
       7. The process of  claim 6 , wherein the modified PET polymer has a disc L* of at least about 80. 
     
     
       8. The process of  claim 7 , wherein the modified PET polymer has a disc L* of at least about 90. 
     
     
       9. The process of  claim 1 , wherein the modified PET polymer has an It.V. of at least about 0.72 dL/g to about 1.1 dL/g. 
     
     
       10. The process of  claim 9 , wherein the modified PET polymer has an It.V. of at least about 0.76 dL/g to about 1.1 dL/g. 
     
     
       11. The process of  claim 10 , wherein the modified PET polymer has an It.V. of at least about 0.80 dL/g to about 1.1 dL/g. 
     
     
       12. The process of  claim 11 , wherein the modified PET polymer achieves the It.V. in the melt phase. 
     
     
       13. The process of  claim 1 , further comprising: continuously
 i. reacting the non-hydrogenated isophthalic acid with the terephthalic acid and the ethylene glycol in an esterification reaction zone to produce an oligomer mixture; 
 ii. further reacting the oligomer mixture to produce the modified PET polymer in a melt-phase polycondensation zone; and 
 iii. optionally further increasing the modified PET polymer It.V. in a solid-state processing zone. 
 
     
     
       14. The process of  claim 13 , wherein a mixture of the non-hydrogenated isophthalic acid, the terephthalic acid, and the ethylene glycol are fed to the esterification zone. 
     
     
       15. The process of  claim 13 , wherein the non-hydrogenated isophthalic acid, the terephthalic acid, and the ethylene glycol are fed to the esterification zone in a feed system comprising a first mixture comprising the non-hydrogenated isophthalic acid and the ethylene glycol and a second mixture comprising the terephthalic acid and the ethylene glycol. 
     
     
       16. The process of  claim 13 , wherein the esterification reaction zone has a throughput of from 500 kg/hr to 175,000 kg/hr. 
     
     
       17. A process for producing a modified PET polymer comprising reacting non-hydrogenated isophthalic acid and terephthalic acid with ethylene glycol to produce the modified PET polymer having a disc L* of at least about 60 and a disc b* of less than about 5, wherein the modified PET polymer comprises:
 i. a carboxylic acid component comprising
 a. about 0.5 mole % to about 7 mole % isophthalic acid residues; 
 b. at least about 90 mole % terephthalic acid residues; and 
 
 ii. a hydroxyl component comprising at least about 90 mole % ethylene glycol residues based upon 100 mole % carboxylic acid component residues and 100 mole % hydroxyl component residues, wherein the non-hydrogenated isophthalic acid is produced by a process consisting essentially of:
 a. oxidizing m-xylene; 
 b. crystallizing isophthalic acid; 
 c. washing the crystallized isophthalic acid; and 
 d. drying the washed isophthalic acid. 
 
 
     
     
       18. The process of  claim 17 , wherein the modified PET polymer comprises:
 i. the carboxylic acid component comprising
 a. about 0.5 mole % to about 7 mole % isophthalic acid residues; 
 b. at least about 93 mole % terephthalic acid residues; and 
 
 ii. a hydroxyl component comprising at least about 95 mole % ethylene glycol residues, 
 based on 100 mole percent of the carboxylic acid component residues and 100 mole percent of the hydroxyl component residues in the modified PET polymer. 
 
     
     
       19. The process of  claim 17 , wherein the carboxylic acid component comprises about 1 mole % to about 4 mole % of the isophthalic acid residues. 
     
     
       20. The process of  claim 17 , wherein the non-hydrogenated isophthalic acid comprises at least:
 i. about 100 ppm to about 10,000 ppm 3-CBA; 
 ii. about 20 ppm to about 500 ppm fluorenones; or 
 iii. at least about 50 ppm to about 10,000 ppm 3-CBA in combination with at least about 10 ppm to about 500 ppm fluorenones. 
 
     
     
       21. The process of  claim 17 , wherein the modified PET polymer has a disc L* of at least about 70. 
     
     
       22. The process of  claim 21 , wherein the modified PET polymer has a disc L* of at least about 80. 
     
     
       23. The process of  claim 17 , wherein the modified PET polymer has an It.V. of at least about 0.72 dL/g to about 1.1 dL/g. 
     
     
       24. The process of  claim 23 , wherein the modified PET polymer has an It.V. of at least about 0.80 dL/g to about 1.1 dL/g. 
     
     
       25. The process of  claim 24 , wherein the modified PET polymer achieves the It.V. in the melt phase. 
     
     
       26. A process for producing a shaped article comprising:
 A. reacting non-hydrogenated isophthalic acid with terephthalic acid and ethylene glycol to produce a modified PET polymer comprising
 i. a carboxylic acid component comprising:
 a. about 0.5 mole % to about 7 mole % isophthalic acid residues; 
 b. at least about 90 mole % terephthalic acid residues; and 
 
 ii. a hydroxyl component comprising at least about 90 mole % ethylene glycol residues, 
 based upon 100 mole % carboxylic acid residues and 100 mole percent hydroxyl component residues in the modified PET having a disc L* of at least about 60 and a disc b* of less than about 5; and 
 
 B. forming a shaped article from the modified PET polymer of step (A). 
 
     
     
       27. The process of  claim 26 , wherein the modified PET polymer comprises:
 i. the carboxylic acid component comprising
 a. about 0.5 mole % to about 7 mole % of the isophthalic acid residues; 
 b. at least about 93 mole % of the terephthalic acid residues; and 
 
 ii. the hydroxyl component comprising at least about 95 mole % of the ethylene glycol residues, 
 based on 100 mole percent of the carboxylic acid component residues and 100 mole percent of the hydroxyl component residues in the modified PET polymer. 
 
     
     
       28. The process of  claim 26 , wherein the carboxylic acid component comprises about 1 mole % to about 4 mole % of the isophthalic acid residues. 
     
     
       29. The process of  claim 26 , wherein the non-hydrogenated isophthalic acid comprises at least:
 i. about 100 ppm to about 10,000 ppm 3-CBA; 
 ii. about 20 ppm to about 500 ppm fluorenones; or 
 iii. at least about 50 ppm to about 10,000 ppm 3-CBA in combination with at least about 10 ppm to about 500 ppm fluorenones. 
 
     
     
       30. The process of  claim 26 , wherein the modified PET polymer has a disc L* of at least about 70. 
     
     
       31. The process of  claim 30 , wherein the modified PET polymer has a disc L* of at least about 80. 
     
     
       32. The process of  claim 26 , wherein the modified PET polymer has an It.V. of at least about 0.72 dL/g to about 1.1 dL/g. 
     
     
       33. The process of  claim 32 , wherein the modified PET polymer has an It.V. of at least about 0.80 dL/g to about 1.1 dL/g. 
     
     
       34. The process of  claim 33 , wherein the modified PET polymer achieves the It.V. in the melt phase.